Mesothelioma: Pleural Mesothelioma

Thoracic oncologist Lee Krug and colleagues have pioneered a multimodal approach to the treatment of pleural mesothelioma that combines surgical removal of cancerous tissue along with chemotherapy and/or radiation treatment.

Pleural mesothelioma is the most common type of mesothelioma. It is found in the pleura, the sacs that protect the lungs.

Treatment for this cancer often includes surgery. In making decisions about surgical treatment we draw from our mesothelioma database(1),(2), which contains information on treatment decisions and outcomes for the more than 1,000 patients with this illness who have been cared for at Memorial Sloan Kettering over the years.

The knowledge gained from this database on mesothelioma – the world’s largest – helps in choosing not only who is a good candidate for surgery, but which type of surgery would be most effective for your disease. Our clinicians and researchers collaborate closely in proposing refinements and new classifications of disease that might aid in personalizing and improving treatment.

We have pioneered a multimodal approach to the treatment of pleural mesothelioma that combines surgical removal of cancerous tissue along with chemotherapy and/or radiation treatment.

In addition to advanced surgical care, our radiation oncologists have developed cutting-edge radiation techniques for treating pleural mesothelioma, such as intensity-modulated radiation therapy (IMRT), which enables targeted radiation to be administered directly to the pleura(3). Clinical trials are under way at Memorial Sloan Kettering to assess the safety and efficacy of this novel approach.

Memorial Sloan Kettering doctors are also exploring the use of novel immunotherapies for mesothelioma that stimulate the body’s immune system to attack and kill cancer cells. Promising approaches to date include tumor vaccines, antibody therapies, T cell–based treatments, and the use of anticancer viruses.

The first step in receiving the appropriate treatment for pleural mesothelioma involves confirming the diagnosis and staging the cancer. Only then will your doctors be able to determine whether surgery, chemotherapy, and/or radiation is the best approach for you.

Diagnosing pleural mesothelioma

At your first visit, the doctor will discuss your medical history to determine whether you have been exposed to asbestos, which is a risk factor for developing this disease. To make a diagnosis, a biopsy is necessary. This involves a surgeon placing a tiny camera through a small incision in your chest wall and removing (through another small incision) a sample of tissue for examination in a laboratory.

At Memorial Sloan Kettering the biopsy procedure is performed via video-assisted thoracic surgery (VATS) while you are under general anesthesia. A biopsy takes less than an hour, and recovery takes a few days. You will also have a physical examination, x-rays, lung function tests, and other imaging tests such as CT and PET scans to determine how extensive your disease is.

Buildup of fluid in the lungs (pleural effusion) that causes shortness of breath is common in people with this illness. If this is the case, our doctors may insert a simple drainage catheter or perform a procedure called thoracentesis to remove the fluid at the same time that a biopsy is taken.

Staging the disease

Staging mesothelioma is an important part of deciding on a treatment plan for you. Our doctors use the TNM staging system, which was developed by the American Joint Committee on Cancer. The stage depends on your tumor’s size (T), whether the cancer has spread to nearby lymph nodes (N), and whether the tumor has metastasized (M) to other parts of the body. Pleural mesothelioma is classified into four stages:

Stage I and II mesothelioma is confined to the pleura on one lung.

Stage III has invaded the mediastinum (the area between the lungs) or involves the lymph nodes.

Stage IV has invaded the chest wall or has spread to other sites in the body.

Surgery and Multimodal Therapy

Most people diagnosed with pleural mesothelioma have disease that is limited to the lining of one lung, and surgery is often considered a treatment option. The decision of whether to operate depends on a number of factors, including your level of fitness, histology results, and the stage of your disease.

At Memorial Sloan Kettering, most patients are considered for an operation called a pleurectomy/decortication to remove the pleura and as much disease tissue as possible. People whose disease is more advanced may require a more aggressive surgery called an extrapleural pneumonectomy, in which we remove the lining of the lung and the affected lung itself, along with the diaphragm on that side of the body and a portion of the lining around the heart. However, only a select group of patients are in strong enough condition to undergo an extrapleural pneumonectomy.

In either scenario, surgery alone is not enough to treat the disease since mesothelioma has a high chance of growing back, so we generally recommend that patients also receive chemotherapy and/or radiation as part of their treatment course.

Memorial Sloan Kettering pioneered this multimodal approach. We first studied how patients fared after being treated with chemotherapy followed by extrapleural pneumonectomy, and then radiation to the entire half of the affected side of the chest(4). After finding that a pleurectomy/decortication may actually be a more effective operation(5) and preferred by patients since it is safer, has a quicker recovery, and spares the lung from being removed – we instituted a new paradigm in which most patients receive chemotherapy followed by pleurectomy/decortication, and then radiation just to the edge of the lung using intensity-modulated radiation therapy (IMRT).

Chemotherapy

Chemotherapy is most often used for patients with advanced pleural mesothelioma. However, it is also used for patients with early-stage pleural mesothelioma before or after surgery.

The most commonly used drugs are pemetrexed (Alimta®) and cisplatin (Platinol®). Studies have shown that treatment with these two drugs can increase survival and improve quality of life in people with mesothelioma. The treatment is given every three weeks, along with a regimen of vitamins to decrease side effects.

Our medical oncologists led a national study(6) assessing the benefit of giving chemotherapy before surgery and radiation.

Radiation Therapy

At Memorial Sloan Kettering we have extensive experience in treating the lining around the lung with a technique called intensity-modulated radiation therapy (IMRT(7)). IMRT uses sophisticated treatment planning and dose-delivery techniques to precisely target a tumor and spare other parts of the body from exposure to radiation. We have also pioneered the incorporation of PET scans into the treatment-planning process. This helps ensure the radiation is reaching all sites of disease requiring treatment.

Our doctors have established that following removal of a lung (an extrapleural pneumonectomy), radiation administered to the entire chest cavity can lower the risk that the disease will come back in this part of the body(8). In people with the lung still in place, the use of radiation therapy is more challenging because it is difficult to deliver adequate doses of radiation to the outside of the lung without damaging the lung itself.

Radiation therapy is typically started four to six weeks after surgery and involves once-a-day sessions for five days a week over the course of five to six weeks.